People are frequently at risk of being infected by airborne pathogens. For the general population, common pathogens include common cold viruses (e.g. rhinoviruses) and influenza virus. Sub-groups of the population, such as hospital patients and hospital employees, may be exposed to, and therefore be at risk of infection by, other pathogens for example Methicillin Resistant Staphylococcus aureus (MRSA) or Mycobacterium tuberculosis (TB). Hospitalised patients are particularly likely to have some level of immuno-suppression, such as elderly people, people with congenital immunodeficiency, people undergoing or shortly following cancer treatment or organ transplantation, and therefore be susceptible to infection. Current methods of preventing infections include vaccination of at-risk groups and/or the wearing of personal protective equipment (PPE) such as face masks which include air filters.
There are drawbacks associated with vaccinating at-risk groups against infection. For example, it is not always possible to know which pathogens are likely to be present. Also, it can be difficult to predict the general type and precise strain of pathogen which is likely to occur. Furthermore, it can be difficult to ensure that all at-risk people are vaccinated. Also, there might not be a vaccine available for the infectious organism in question; and a vaccine may not be suitable for certain groups of people such as immuno-suppressed individuals.
Current personal protective equipment includes face masks such as surgical masks and P3 face masks. Such masks include air filters. Examples of face masks include the FFP3 cone style face mask with valve. Such a mask typically has a polymer outer facing which is lightweight and offers good breathability. The polymer outer facing may be ethylene propylene diene monomer (EPDM) rubber. The mask also typically has a melt blown filter media which has a bacterial filter efficiency of 99% for bacteria of 3 μm size. This provides good protection from air-borne bacteria. The mask also typically has a particle filtration efficiency of 99% for 0.3 μm particles and a differential pressure (delta P) of less than 6. This provides good breathability. The air valve is typically a one-way plastic valve which provides comfort and ease of breathing. The mask also typically includes a compliant cuff of a soft, latex-free material which provides a seal between the mask and the face of the user with good skin comfort. These masks provide a physical barrier between the user and the air and therefore prevent bacteria from being breathed in by the user. The masks also have a tendency to become blocked which causes breathing difficulties and can result in the mask leaking thus allowing bacteria to enter the user.
Chinese patent application CN1600383 discloses equipment for isolating and sterilizing infectious diseases to prevent release of the infectious disease from a patient to the environment. The equipment combines a filter with a high-voltage electrostatic field, a sterilizing UV lamp, an uninterruptible power supply and an electronic monitor with a microprocessor. This has the result that infectious particles are removed from the air. The equipment of CN1600383 is large.
Surgical masks are disposable devices that cover the mouth and nose of a care-giver during medical procedures. They help protect a care-giver against micro-organisms, body fluids, and small particles in the air by filtering the air before it is delivered to the care-giver. Furthermore, they protect the patient from inhaling micro-organisms and body fluids which may be exhaled by the care-giver. A problem of such masks is that they have a high resistance against air and can therefore make breathing difficult. Furthermore, if not fitted carefully to the face of the user, such masks leak and therefore do not provide the protection expected and required. They also provide limited or no protection against pathogens transmitted as aerosols, that is particles with sizes of less than or equal to 5 μm diameter.
Current devices work by preventing microorganisms from contacting and/or being inhaled by the user of the device. That is, the devices are configured to prevent microorganisms from exiting the device. Such prevention may be achieved through the inclusion of a barrier such as a filter. A disadvantage of use of a filter is that it may become clogged and therefore prevent air from passing through the filter and or result in leakage around the filter thus allowing microorganisms to pass around the filter and consequently reach the user and thus rendering the device useless.